This proposal addresses the general question of how codes or labels attached to certain events in the environment influence attention to those events. The "codes" studied in the research proposed here are overt forms of instrumental behavior which are differential with respect to the events coded. The research focuses on the conditions under which attention to these coding responses compete with attention to the external events which give rise to them. More specifically, the studies address questions regarding how selective attention to a coding-response cue changes as a function of how noticeable it is (its relative salience), how well it predicts biologically important events in the environment (its relative validity), and its temporal relationship with respect to the external cue which supports it. Towards this end, pigeons will be trained on two-choice conditional discrimination tasks in which different visual stimuli (the external events) and different patterns of responding (the coding responses) provide redundant cues for correct choices. Attention to each cue is then assessed following task acquisition by presenting it separately. Overshadowing and blocking procedures will be used to manipulate the degree to which subjects attend to each cue during training. The results from these studies will have important implications for attentional mechanisms involving response-produced cues, expectancies of future reward events, and redundant stimuli whose presence depends upon the occurrence of other environmental stimuli. They will also bear upon the general issue of whether or not similar associative processes underlie instrumental and classical conditioning. The project has potential clinical relevance for psychological and psychosomatic dysfunctions for which successful therapeutic intervention depends upon the patient's ability to selectively attend to inappropriate behavioral responses.